A corneal ulcer is a loss of corneal tissue extending beyond a simple surface erosion. It must be assessed rapidly by an ophthalmologist: depending on cause and depth, the outcome can range from healing without sequelae to a permanent scar on the visual axis.
Symptoms that should raise concern:
An important caveat: in neurotrophic keratitis, the cornea has lost its sensation. The ulcer may then be substantial without pain, dangerously delaying consultation. Unexplained vision loss or redness, even painless, therefore warrants examination — particularly after ocular herpes, ophthalmic shingles, corneal surgery, or in a diabetic patient.
| Cause | Typical context |
|---|---|
| Bacterial infection | Contact lens wear, trauma, already compromised eye. Rapid course, white spot, discharge. |
| Corneal herpes | Possible recurrences, characteristic ulcer appearance. Contraindicates certain treatments. |
| Acanthamoeba | Contact lenses, tap water, swimming pools. Very intense pain, often delayed diagnosis. |
| Severe dry eye | Sjögren's syndrome, eyelid disease, environment. |
| Neurotrophic keratitis | After herpes, shingles, surgery, diabetes. Often painless, persistent ulcer. |
| Trauma, burn | Foreign body, chemical splash. A chemical burn is an immediate emergency. |
| Inflammatory cause | Autoimmune disease, rheumatoid arthritis: peripheral ulcers, risk of melting. |
Contact lens wear is the leading risk factor for infectious ulcers in young people. High-risk behaviours are well identified: sleeping in lenses, exceeding the intended wearing time, rinsing the case or lenses with tap water, swimming or showering while wearing lenses.
The reference examination is slit-lamp examination with fluorescein instillation: this dye binds to areas lacking epithelium and makes the ulcer visible under blue light. It allows assessment of the size, depth and appearance of the ulcer — key elements in distinguishing infectious from non-infectious causes.
Corneal sensation is also tested: reduced sensation points to a neurotrophic origin and completely changes management. If infection is suspected, samples may be taken before starting treatment, to identify the causative organism.
Treatment depends closely on the cause, which is why self-medication is risky: drops suited to one cause may worsen another. Broadly:
Corticosteroids deserve special mention: useful to limit inflammatory scarring in some situations, they can dramatically worsen herpetic, fungal or amoebic infection. Their prescription is strictly a matter for the ophthalmologist, after precise diagnosis. All available therapeutic agents, with their evidence levels, are detailed in the review of factors modulating corneal healing.
An ulcer that has not closed after about two weeks of appropriate treatment defines a persistent epithelial defect. This is not inevitable, but a signal: there is an obstacle to healing that must be identified and treated — severe dryness, loss of corneal sensation, diabetes, eye-drop toxicity, limbal stem cell deficiency.
The risk in these persistent forms is stromal melting: an imbalance between collagen-degrading enzymes and their inhibitors leads to progressive corneal thinning, up to the risk of perforation. It is precisely this tipping point — healing by fibrosis or melting — described in the work on epithelial-stromal interactions.
An ulcer limited to the epithelium heals without trace. As soon as the stroma is involved, a scarring opacity is common and usually permanent. Its impact depends mainly on location: a small central scar in the visual axis is far more disabling than a larger peripheral opacity. Irregular astigmatism may also persist. When the scar durably compromises vision, corneal transplantation may be discussed, once the acute episode has settled.
Post-surgical or spontaneous, specialised care is available.
Urgent consultation →This information is provided for educational purposes and does not replace a consultation. A corneal ulcer requires ophthalmological examination: only this can determine its cause and depth and allow appropriate treatment. If in doubt, seek care without delay.
